Note: This technique was made possible in the 2024 release.

By default, pipe elevations are based on an elevation of zero or the ground. What if you need to reference a building or structure with multiple floors and want the pipe elevation to reference the floor beneath it? Now you can, due to an enhancement to Calculated Properties.

Example

In the image below, you will see a structural platform with a top of steel elevation of 40’-0”. Some of the horizontal pipe has a COP elevation of 46’–3 5/8” from the ground or zero.

Figure 1: Pipe in model, COP Elevation.

We would like to have the COP elevation calculated from the virtual floor beneath the pipe. To do this, you will go into Project Setup and add two new properties. The first one will store the height of the desired floor above the ground. The second one will calculate the difference between that value and the actual COP elevation.

Property #1: Relative Floor Height

1. Go into Project Setup and navigate to the following branch:
2. Plant 3D DWG Settings > Plant 3D Class Definitions > Piping and Equipment > Pipe Run Component > Pipe
3. On the right, click Add.
4. Enter FloorHeight for the Property Name, and Floor Height (inches) for the Display Name.
5. For the Type, choose Numeric and click OK.
6. In the main dialog, click Apply and stay in Project Setup.

Property #2: Relative Floor Height

1. Still in Project Setup, click Add.
2. Enter RelativeFloorHeight for the Property Name, and Relative Floor Height for the Display Name.
3. Choose Calculated for the type.
4. Next, copy/paste the following string into the Calculated Property Expression

Split(("Position Z"-FloorHeight)/12,'.',1) || '''-' || ToString(Round(ToNumber('.' || Split(("Position Z"-FloorHeight)/12,'.',2)) * 12, 4)) || '"'

[Credit: This string was provided by the Autodesk Support Team.]

5. Click Add Property.

To test this, I opened the piping model, selected a horizontal pipe, went to Properties, and entered 480 (40’-0”) in the new Floor Height (inches) property. This property will be located under the General group of the Properties palette. To make this work correctly, the value must be entered in inches.

Figure 2: COP elevation calculated based on 40’-0” (480 in) floor height.

Notice that the Relative Floor Height property has been calculated. However, the inches will be in decimal format. Per Autodesk, it is not possible to convert decimal to fractional representation at this time.

NOTE: In the event the calculated property is empty, copying/pasting the string above into the calculated property may not work from here. If it doesn’t, try pasting into Notepad first, then again into the property. If that doesn’t work, you must enter it manually using the tools within the property. Be careful with the single and double quotes as they tend to be difficult to see. I did my best to provide the string so that you can copy/paste.

The Catch

In the event you have a pipe elevation that has zero inches, such as 46’-0”, the Relative Floor Height will read 6’-“. Notice that the zero will not be shown for the inches, which is not the correct display.

Figure 3: Calculated relative floor height when there are no inches.

You’ll need another calculated property to address this.

Property #3: Relative Floor Height Rounded

(Use this property when there are no inches in the calculated floor height.)

1. Go into Project Setup and navigate to the following branch:
2. Plant 3D DWG Settings > Plant 3D Class Definitions > Piping and Equipment > Pipe Run Component > Pipe
3. On the right, click Add.
4. Enter RelativeFloorHeightRounded for the Property Name, and Relative Floor Height Rounded for the Display Name.
5. Paste the following string into the Calculated Property Expression

Split(("Position Z"-FloorHeight)/12,'.',1) || '''-0"'

This string will append a zero behind the dash.

Figure 4: Additional property available when relative floor height has no inches.

You’ll want this additional property so that the value displayed in the model appears complete. When the calculated property displays the inches, you can ignore this one.

These new properties can now be used with new annotations for your drawings.

Create Annotations for the New Calculated Properties

Although this article does not give step-by-step instructions for creating annotations, the overall idea is provided. Go back into Project Setup to the Pipe class definition and add a new annotation based on the out of box COP annotation. Edit the block, modify the attribute, and replace it with the new calculated property. When the time comes to annotate an orthographic drawing, you can use it as needed. If you want one for pipe with no inches in its elevation, add another annotation for that too.

Here’s an example of an annotation for the RelativeFloorHeight property:

Figure 6: Annotation format for the Relative Floor Height property.

The second annotation would use TargetObject.RelativeFloorHeightRounded in the same manner as above.

Here’s an example of one of a new annotation in a drawing:

Figure 7: Relative annotation in an elevation view.

Remember, the calculated property will show the inches in decimal format and it is not currently possible to convert to a fraction, per Autodesk.

You might annotate pipe elevations in a plan, elevation, or section view. You can create the additional annotations depending on the output you need in your Ortho views. But when you want a pipe elevation based on the floor beneath it, these new properties will help. It won’t be necessary to fill in these properties for all pipes; only the ones you want to keep track of.

If you need further assistance, don’t hesitate to contact us for more help.